References of "Plapper, Peter 50002870"
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See detailLessons from social network analysis to Industry 4.0
Omar, Yamila UL; Minoufekr, Meysam UL; Plapper, Peter UL

in Manufacturing Letters (in press)

With the advent of Industry 4.0, a growing number of sensors within modern production lines generate high volumes of data. This data can be used to optimize the manufacturing industry in terms of complex ... [more ▼]

With the advent of Industry 4.0, a growing number of sensors within modern production lines generate high volumes of data. This data can be used to optimize the manufacturing industry in terms of complex network topology metrics commonly used in the analysis of social and communication networks. In this work, several such metrics are presented along with their appropriate interpretation in the field of manufacturing. Furthermore, the assumptions under which such metrics are defined are assessed in order to determine their suitability. Finally, their potential application to identify performance limiting resources, allocate maintenance resources and guarantee quality assurance are discussed. [less ▲]

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See detailDissimilar Laser Micro-Welding of Nickel Wire to CuSn6 Bronze Terminal
Amne Elahi, Mahdi UL; Plapper, Peter UL

in Transactions of the Indian Institute of Metals (2018)

In the present study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Considering the geometry of parts to be welded and also ... [more ▼]

In the present study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Considering the geometry of parts to be welded and also requirement of mechanical properties, spatial modulation of the laser beam was needed to be implemented to achieve a sound joint. Tensile-shear test and optical microscopy were employed to represent the mechanical properties and melt pool geometry of the joints. All welds were done by power modulation of the laser beam to better control the energy input at several feed rates and three different beam trajectories. Results showed that the shear load of the joint could be controlled by feed rate and the trajectory of the laser beam. Considering the material combination of the study that were nickel and CuSn6 bronze, which represented solubility in solid state, a joint stronger than base wire metal was achieved by defining a proper spatial modulation and feed rate of the laser beam. [less ▲]

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See detailA survey: The usage of Augmented Reality in Industry
Gallala, Abir UL; Hichri, Bassem UL; Plapper, Peter UL

in Robotix-Academy Conference for Industrial Robotics 2018 (2018, November 01)

Human-Robot-Interaction technologies in industry 4.0 and modern manufacturing are more and more growing. Using off-line robot programming methods such as Augmented Reality (AR) could gain time and money ... [more ▼]

Human-Robot-Interaction technologies in industry 4.0 and modern manufacturing are more and more growing. Using off-line robot programming methods such as Augmented Reality (AR) could gain time and money as well as improve programming and repair tasks. This paper is a study of the use of AR in smart factories. [less ▲]

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See detailAutogenous Laser welding of copper to aluminium
Mathivanan, Karthik UL; Plapper, Peter UL

Poster (2018, September 13)

This work investigates laser joining of copper sheets to aluminium in overlap configuration. Dissimilar Cu-Al connections are widely used in the electrical and electronics applications e.g. battery and ... [more ▼]

This work investigates laser joining of copper sheets to aluminium in overlap configuration. Dissimilar Cu-Al connections are widely used in the electrical and electronics applications e.g. battery and solar panels.Joining these materials is a very critical assembly process. The laser welding from the aluminium surface to copper (Al-Cu) is well described in the literature .But there is no data concerning the laser seam welding from the copper side to join with aluminium i.e Cu-Al.The selection of aluminium surface to irradiate is mainly because of poor absorption of copper to laser in IR region.But high intensities of about 100 MW/cm2 allow for initial vaporization of copper surface.Once the keyhole is generated, absorption of laser light is improved.Thereby high power lasers allow for successful penetration of copper surface to produce a joint with aluminium. The main objective is to investigate the approach of dissimilar laser welding starting from the copper surface to aluminium.The effect of process parameters on the shear force, microstructure and weld pool dimensions are studied.An experimental design is realized to see the effect of laser irradiation of copper surface (Cu-Al) in contrast to aluminium surface(Al-Cu). The selection of aluminium or copper surface is mainly dependent on the laser power.With the high power disk laser the possibility of joining from the copper side was evident and results of joining copper to aluminium and aluminium to copper are comparable.Therefore welding from a highly reflective surface to achive a comparable shear strength is demonstrated. [less ▲]

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See detailLaser micro-welding of wire to flat geometry for dissimilar materials in an electromechanical application
Amne Elahi, Mahdi UL; Plapper, Peter UL

Poster (2018, September 11)

In the presented study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Laser welding offers variety of advantages compared to the ... [more ▼]

In the presented study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Laser welding offers variety of advantages compared to the current joining processes for this application however, considering the geometry of parts to be welded also mechanical properties requirement, an accurate spatial modulation of laser beam should be implemented to achieve a sound joint. Tensile shear test and optical microscopy were employed to represent the mechanical properties and melt pool geometry of the joint. All welds were done by power modulation of the laser beam to better control the energy input at several feed rates and three different beam trajectories. Results show that the shear load of the joint can be controlled by feed rate and the trajectory of the laser beam. The material combination of the study (Nickel and CuSn6), represents solubility in solid state therefore, by defining a proper spatial modulation of the laser beam a joint stronger than base wire metal is achievable. Figure 1 represents schematics of weld components. [less ▲]

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See detailInfluence of laser parameter on weld bead shape and process stability of laser welded steel sheets
Schiry, Marc UL; Plapper, Peter UL

in Proceedings of 10th Conference on Photonic Technologies LANE 2018 (2018)

Laser butt-welding of dissimilar heat sensitive materials is one of the most challenging tasks. Significant differences in melting and transition temperatures are typical and occur frequently. Therefore ... [more ▼]

Laser butt-welding of dissimilar heat sensitive materials is one of the most challenging tasks. Significant differences in melting and transition temperatures are typical and occur frequently. Therefore, accurate control of the temperature profile at the interface of the weld is essential. In this paper, the influence of the laser parameter power and velocity, as well as laser spot diameter on the laser process were investigated. It is shown that the beam diameter has a significant impact on the weld bead formation. Further variation of the type of shielding gas showed an effect on the bead geometry depending on the used laser spot diameter. Spectroscopic process observations showed a significant impact of the spot diameter and shielding gas on the energy input and the efficiency of the laser process. A homogeneous damping effect of the laser radiation was obtained by using the larger fiber diameter accompanied with a higher overall intensity of process radiation. [less ▲]

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See detailComposition and phases in laser welded Al-Cu joints by synchrotron x-ray microdiffraction
Schmalen, Pascal Guy UL; Plapper, Peter UL; Peral Alonso, Inmaculada UL et al

in Proceedings of 10th CIRP Conference on Photonic Technologies [LANE 2018] (2018)

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical ... [more ▼]

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical micrographs. Transmission microdiffraction offers the spatial resolution and beam flux necessary to study the intermetallic phases, which in conjunction with the excellent contrast of etched micrographs, rendered possible the phase identification. It was found that the major phases are Al2Cu (θ), Al4Cu9 (γ1) and AlCu (η2) were formed. The Al3Cu4 (ζ1) and δ phases where formed in less amount and found to be the primary cause for cracks inside the weld seam and therefore for the failure of the joint. [less ▲]

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See detailSpectroscopic Studies of dissimilar Al-Cu laser welding
Schmalen, Pascal Guy UL; Plapper, Peter UL

in proceedings of asme msec 2018 (2018)

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be ... [more ▼]

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be suitable for process monitoring during laser welding. For aluminum, the double peak at 394.4 and 396.1 nm was studied, for cu the 578 nm peak was studied. The characteristic peaks were observed by multiple photodiodes equipped with narrow optical filters with varying FWHM. Analyzing the plasma emissions of the process enabled to detect material changes in the plasma plume. This novel method has the advantage of higher sampling rate combined with reduced costs compared to a spectrometer and is thus able to capture the process dynamics. [less ▲]

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See detailCILAP-Architecture for Simultaneous Position- and Force-Control in Constrained Manufacturing Tasks
Klecker, Sophie UL; Hichri, Bassem UL; Plapper, Peter UL

in ICINCO 2018 Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics Volume 2 (2018, July)

This paper presents a parallel control concept for automated constrained manufacturing tasks, i.e. for simultaneous position- and force-control of industrial robotic manipulators. The manipulator’s ... [more ▼]

This paper presents a parallel control concept for automated constrained manufacturing tasks, i.e. for simultaneous position- and force-control of industrial robotic manipulators. The manipulator’s interaction with its environment results in a constrained non-linear switched system. In combination with internal and external uncertainties and in the presence of friction, the stable system performance is impaired. The aim is to mimic a human worker’s behaviour encoded as lists of successive desired positions and forces obtained from the records of a human performing the considered task operating the lightweight robot arm in gravity compensation mode. The suggested parallel control concept combines a model-free position- and a model-free torque-controller. These separate controllers combine conventional PID- and PI-control with adaptive neuro-inspired algorithms. The latter use concepts of a reward-like incentive, a learning system and an actuator-inhibitor-interplay. The elements Conventional controller, Incentive, Learning system and Actuator-Preventer interaction form the CILAP-concept. The main contribution of this work is a biologically inspired parallel control architecture for simultaneous position- and force-control of continuous in contrast to discrete manufacturing tasks without having recourse to visual inputs. The proposed control-method is validated on a surface finishing process-simulation. It is shown that it outperforms a conventional combination of PID- and PI-controllers. [less ▲]

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See detailApplication of Value Stream Management to enhance product and information flows in supply chain networks - based on the example of web-based automotive retail business
Plapper, Peter UL; Oberhausen, Christof UL; Minoufekr, Meysam UL

in Management and Production Engineering Review (2018), 9(2), 13-19

Due to globalized business operations, companies in different economic sectors are part of complex supply chain networks. Their value-added processes comprise product and information flows, e.g. with a ... [more ▼]

Due to globalized business operations, companies in different economic sectors are part of complex supply chain networks. Their value-added processes comprise product and information flows, e.g. with a focus on manufacturing, service or trade. Until the final product is delivered to the end customer, it needs to pass many different processes in cooperating organizations. As a result, there a lot of business-to-business (B2B) interactions with cross-enterprise transactions, often including cross-border communications and sometimes even cross-industry trades with technological and often cultural implications. Especially the interfaces of supply chain networks are prone to inefficiencies, misunderstandings and delays due to a lack of standardized B2B transactions, which leads to waste in form of rework, errors and mistakes. In addition, new customers are hard to find for the manufacturing or trading company, since potential customers are so far limited to a regional network. The advantages of extending the customer base still need to be explored by many organizations. This paper discusses the opportunities by streamlining the communication along supply chain networks in a general fashion and then describes the application in a B2B automotive retail business. A concept of a web-based trading platform, which provides a seamless service for all steps of a convenient and efficient used vehicle remarketing business, is developed. It includes all phases, like offering and price finding in a comprehensive online platform, which also covers further activities, such as logistic services, financial transactions, and a mandatory feedback loop. The suggested B2B vehicle-trading platform enables a quick turnover of each transaction, which is analyzed and optimized based on the application of cross-enterprise Value Stream Management. [less ▲]

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See detailLearning-While Controlling RBF-NN for Robot Dynamics Approximation in Neuro-Inspired Control of Switched Nonlinear Systems
Klecker, Sophie UL; Hichri, Bassem UL; Plapper, Peter UL

in Artificial Neural Networks and Machine Learning; ICANN 2018 part 3 (2018)

Radial Basis Function-Neural Networks are well-established function approximators. This paper presents an adaptive Gaussian RBF-NN with an extended learning-while controlling behaviour. The weights ... [more ▼]

Radial Basis Function-Neural Networks are well-established function approximators. This paper presents an adaptive Gaussian RBF-NN with an extended learning-while controlling behaviour. The weights, function centres and widths are updated online based on a sliding mode control element. In this way, the need for fixing parameters a priori is overcome and the network is able to adapt to dynamically changing systems. The aim of this work is to present an extended adaptive neuro-controller for trajectory tracking of serial robots with unknown dynamics. The adaptive RBF-NN is used to approximate the unknown robot manipulator dynamics-function. It is combined with a conventional controller and a bio-inpsired extension for the control of a robot in the presence of switching constraints and discontinuous inputs. Its learned goal-directed output results from the complementary action of an actuator, A, and a prventer, P. The trigger is an incentive, I, based on the weighted perception of the enviornment. The concept is validated through simulations and implementation on a KUKA LWR4-robot. [less ▲]

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See detailAluminum pretreatment by a laser ablation process: influence of processing parameters on the joint strength of laser welded aluminum – polyamide assemblies
Al Sayyad, Adham UL; Bardon, Julien; Hirchenhahn, Pierre et al

in Procedia CIRP (2018)

Laser welding of metal – polymer assemblies is an innovative bonding process. It was already demonstrated that laser surface pretreatments of aluminum (Al), prior to laser welding with a polymer, impacts ... [more ▼]

Laser welding of metal – polymer assemblies is an innovative bonding process. It was already demonstrated that laser surface pretreatments of aluminum (Al), prior to laser welding with a polymer, impacts joints strength. This work adopts a design of experiments (DoE) approach to investigate the influence of several Al laser ablation parameters on joint strength of laser welded Al – polyamide (PA6.6) assemblies. Significant parameters were highlighted, process window was outlined, and optimal parameters were identified. After assembly failure, the joint area was evaluated using optical microscopy. Depending on the laser ablation parameters, the joint area can be enhanced resulting in a significant increase in the corresponding bearable shear load. [less ▲]

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See detailContinuous Improvement of complex process flows by means of StreaM
Oberhausen, Christof UL; Minoufekr, Meysam UL; Plapper, Peter UL

Presentation (2017, December 11)

In numerous sectors and industries worldwide, there is a trend towards an intercompany and often international division of value creation and related work tasks. To overcome the challenges of complex ... [more ▼]

In numerous sectors and industries worldwide, there is a trend towards an intercompany and often international division of value creation and related work tasks. To overcome the challenges of complex cross-enterprise supply chain networks, innovative approaches to visualize, assess and enhance value streams are sought. The StreaM method, which is described in this paper, enables a comprehensive analysis, design and planning of cross-company product and information flows on different levels of value stream detail. At the same time, the entire methodology is based on a common understanding of key symbols, parameters and calculation procedures. In addition, the use of the developed StreaM method and the associated model in a case study proves its practical applicability in an industrial setting. In further validation projects, the transfer of the “Standardized cross-enterprise Value Stream Management Method” to other industry sectors is envisaged to continuously improve energy, trade or service processes. [less ▲]

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See detailContinuous Improvement of Complex Process Flows by Means of StreaM as the “Standardized Cross-Enterprise Value Stream Management Method”
Oberhausen, Christof UL; Minoufekr, Meysam UL; Plapper, Peter UL

in Proceedings of 2017 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM) (2017, December)

In numerous sectors and industries worldwide, there is a trend towards an intercompany and often international division of value creation and related work tasks. To overcome the challenges of complex ... [more ▼]

In numerous sectors and industries worldwide, there is a trend towards an intercompany and often international division of value creation and related work tasks. To overcome the challenges of complex cross-enterprise supply chain networks, innovative approaches to visualize, assess and enhance value streams are sought. The StreaM method, which is described in this paper, enables a comprehensive analysis, design and planning of cross-company product and information flows on different levels of value stream detail. At the same time, the entire methodology is based on a common understanding of key symbols, parameters and calculation procedures. In addition, the use of the developed StreaM method and the associated model in a case study proves its practical applicability in an industrial setting. In further validation projects, the transfer of the “Standardized cross-enterprise Value Stream Management Method” to other industry sectors is envisaged to continuously improve energy, trade or service processes. [less ▲]

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See detailNeuro-Inspired Reward-Based Tracking Control for Robotic Manipulators with Unknown Dynamics
Klecker, Sophie UL; Hichri, Bassem UL; Plapper, Peter UL

in Proceedings of the 2017 2nd International Conference on Robotics and Automation Engineering (ICRAE) (2017, December)

Tracking control for robotic manipulators is required for numerous automation tasks in manufacturing engineering. For this purpose, model-free PD-controllers are largely implemented by default in ... [more ▼]

Tracking control for robotic manipulators is required for numerous automation tasks in manufacturing engineering. For this purpose, model-free PD-controllers are largely implemented by default in commercially available robot arms and provide satisfactory performance for simple path following applications. Ever more complex automation tasks however ask for novel intelligent and adaptive tracking control strategies. In surface finishing processes, discontinuous freeform paths as well as changing constraints between the robotic end-effector and its surrounding environment affect the tracking control by undermining the stable system performance. The lacking knowledge of industrial robot dynamic parameters presents an additional challenge for the tracking control algorithms. In this paper the control problem of robotic manipulators with unknown dynamics and varying constraints is addressed. A robust sliding mode controller is combined with an RBF (Radial Basis Function) Neural Network-estimator and an intelligent, biomimetic BELBIC (Brain Emotional Learning-Based Intelligent Control) term to approximate the nonlinear robot dynamics function and achieve a robust and adaptive tracking performance. [less ▲]

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See detailInfluence of laser ablation and plasma surface treatment on the joint strength of laser welded aluminum-polyamide assemblies
Al Sayyad, Adham UL; Bardon, Julien; Hirchenhahn, Pierre et al

Scientific Conference (2017, September 14)

Laser assembly of a metal with a polymer is an innovative process for the development of hybrid lightweight structures. It was already demonstrated that surface treatment of aluminum prior to laser ... [more ▼]

Laser assembly of a metal with a polymer is an innovative process for the development of hybrid lightweight structures. It was already demonstrated that surface treatment of aluminum prior to laser joining has a critical influence on joint strength of laser assembly with polyamide. In this work, further investigation of the influence of surface treatment prior to laser assembly is carried out. In particular, two kind of surface modification pretreatments of aluminum, laser ablation and plasma surface modification, in combination with plasma surface pretreatment of polyamide, were investigated. Surface properties of aluminum and polyamide after pretreatment are compared to their untreated state. More precisely, surface chemistry, surface energy and roughness characteristics are evaluated by X-ray photoelectron spectroscopy (XPS), sessile drop tests and 3D profilometry, respectively. Joint strength of laser assembly of treated aluminum and polyamide is reported. The more influential surface characteristics for the improvement of joint strength are determined, paving the way to significant advances in metal-polymer laser assembly technology. [less ▲]

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See detailRobotix-Academy Conference for Industrial Robotics (RACIR) 2017
Müller, Rainer; Plapper, Peter UL; Brüls, Olivier et al

Book published by Shaker Verlag - 1st ed (2017)

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See detailResistance measurement of dissimilar Al/Cu laser welds
Schmalen, Pascal Guy UL; Plapper, Peter UL

in Proceedings of LPM2017 - the 18th International Symposium on Laser Precision Microfabrication (2017)

Aluminum and Copper were joined using the laser-based braze-welding process. By avoiding the intermixture of both conductive materials, the formation of brittle intermetallic compounds is strongly reduced ... [more ▼]

Aluminum and Copper were joined using the laser-based braze-welding process. By avoiding the intermixture of both conductive materials, the formation of brittle intermetallic compounds is strongly reduced. This results in a tough, ductile connection with reduced electric resistance. This paper de-scribes a method, which is based on the 4-wire method, to measure the resistance of the weld seam. The arrangement of the conductive electrodes directly on top and bottom of the weld seam signifi-cantly increases the accuracy of the measured resistances, thus offers a direct estimation of the inter-metallic layer thickness. The electric measuring of the layer thickness is a non-destructive method, which assists in the reduction of the post-process effort (cross sections, pull tests, hardness measure-ments) and decreases the lead-time by reducing the time needed for the identification of suitable laser process parameters. [less ▲]

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See detailTowards Intelligent Robot Assistants for the non-destructive Disassembly of End of Life Products
Jungbluth, Jan UL; Plapper, Peter UL; Gerke, Wolfgang

in Plapper, Peter; Hichri, Bassem (Eds.) Robotix-Academy Conference (2017, May 06)

The effective collaboration between humans and robots in complex and task rich environments like End of Life product disassembly depends on the ability of the robot to anticipate the workflow as well as ... [more ▼]

The effective collaboration between humans and robots in complex and task rich environments like End of Life product disassembly depends on the ability of the robot to anticipate the workflow as well as the assistance the human co-worker wants. Our approach towards such an intelligent system is the development of an informed software agent that controls the robot assistance behavior. We inform the agent with procedural and declarative knowledge about the disassembly domain through models of the product structure and actor/object models. The product structure is then transformed to a directed graph and used to build, share and define a goal-orientated coarse workflow. Depending on the tasks and wanted assistance, the system can generate adaptable and detailed workflows through searching in the situation space on the basis of predefined and task dependent actions. The created detailed workflow consists of a sequence of actions that are used to call, parameterize and execute robot programs for the fulfillment of the assistance. The aim of this research is to equip robot systems with higher cognitive skills to allow them to be autonomous in the performance of their assistance to improve the ergonomics of disassembly workstations. [less ▲]

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See detailRobust BELBIC-Extension for Trajectory Tracking Control
Klecker, Sophie UL; Hichri, Bassem UL; Plapper, Peter UL

in Journal of Mechanics Engineering and Automation (2017), 7(2),

In real-life trajectory tracking applications of robotic manipulators uncertain robot dynamics, external disturbances and switching constraints which cannot be accommodated for by a conventional ... [more ▼]

In real-life trajectory tracking applications of robotic manipulators uncertain robot dynamics, external disturbances and switching constraints which cannot be accommodated for by a conventional controller affect the system performance. We suggested an additional control element combining sliding mode and bio-mimetic, neurologically-inspired BELBIC (brain emotional learning-based intelligent control). The former is invariant to internal and external uncertainties and guarantees robust behavior. The latter is based on an interplay of inputs relating to environmental information through error-signals of position and sliding surfaces and of emotional signals regulating the learning rate and adapting the future behaviour based on prior experiences and with the goal to maximize a reward function. We proofed the stability and the performance of the suggested control scheme through Lyapunov theory and numerical simulations, respectively. [less ▲]

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